Nutrient Intakes of Vegetarians and Vegans

Vitamin A is listed as measured in micrograms of retinol, rather than retinol activity equivalents (RAE). Plant foods do not contain retinol, yet vegans are listed as having an intake of retinol. But that intake seems very low compared to what would be expected if carotenoids were included. So, it is unclear how the amount of vitamin A was determined.

AHS-2:

Data includes fortified foods and supplements. No separate analysis was given without supplements included.

These nutrient intakes were based on food frequency questionnaires (FFQ) which are the least accurate way of measuring nutrient intakes. FFQs involve asking someone how often they eat a long list of foods. Two better ways to measure nutrient intakes are to ask participants to keep a food diary, or to analyze duplicate portions in a laboratory. EPIC-Oxford has plans to report nutrient intakes by using food dairies among a sample of the population. The authors reported that:

Seven-day food diaries were completed by 31,000 participants and these will provide further information on energy intake. Preliminary analysis of a sample of 150 food diaries indicates that the FFQ does indeed underestimate intakes of energy, and therefore of most nutrients, among vegans (unpublished data).